Panel structure and a method of assembling panels on a support



Patented Dec. 11, 1951 UNITED STATES PATENT OFFICE PANEL STRUCTURE AND A METHOD OF ASSEMBLING PANELS ON A SUPPORT 6 Claims.

This invention relates to a panel structure and a method of assembling panels on a support, and more particularly to mounting plywood and other panel structures on a support in such a manner as to make a smooth surface and to conceal the joint.

It is customary to mount plywood panels on the studding and joists of buildings to form a Wall or floor which may be painted or otherwise suitably treated. The panels of plywood come in standard sizes, such as 4' X 8', and this ordinarily requires that two adjacent panels make a butt joint and thus leave a crack there between. This crack is unsightly; and various attempts have been made to fill it with plastic material or otherwise to conceal it under cloth, paper or other strip material.

It has been proposed to groove the edges of the plywood panels used for a wall and to interfit the yoke shaped flanges of the grooved parts. This has eliminated the crack between the two panels but leaves a step of about 9;" thickness at each end and thus defeats the attempt at concealin the joint; hence, this type of wall does not compare favorably with a smooth plaster wall. Another method has involved mountin a moulding strip over the crack to conceal it but leaving a ridged frame around the panel.

It has also been proposed to secure 2-ply plywood strips together by means of glued joints of various forms. The joint may be a simple scarf out where each piece has its edge bevelled and the bevels are overlapped with glue there between; or one piece may have a V-groove and the other shaped to fit therein. This type of joint requires that the parts be secured together with the aid of a press which holds both ends of the strips while the middle portions are held under pressure and heat is applied to set the cement; or this same operation may be done in a press with a cold-setting glue. That method is applicable only for use in the factory, because it requires a heavy press to hold the parts in position while the cement sets, and it cannot be used for assembling and buildin upa wall or a floor.

The primary object of my invention is to overcome such problems and to assemble a building wall panel structure on a support in such a manner that the joints between adjacent panels are concealed and the surface appears to be con-' tinuous and smooth.

A further object of the invention is to provide a method of building up a building wall panel structure in such a'manner that adjacent 2 panels are so connected by wooden strips that the grains of the juxtaposed veneers of the panels and strips form a substantially continuous and uinform structure at the joint.

A still further object of this invention is to provide a method of assembling building wall panels and securing them on a support, which can be carried on at the point of installation and without requiring special apparatus, such as a press, to secure the panels in a place.

Another object is to provide a building wall made of plywood panels which are so connected at the joints by a multi-ply veneer strip therebetween as to provide a substantially continuous grain structure across each joint and provide a one piece integral well. Other objects will be apparent in the following disclosure.

In accordance with my invention, I propose to form a shallow channel at the joint by grooving the adjacent portions of two abutting panels and to cement in the channel a wooden strip whose surface lies flush with the panels.

Referring to the drawings which illustrate a preferred embodiment of the invention:

Fig. 1 is a fragmentary perspective view of portions of three panels assembled on a joist or stud with a joint concealing strip in position; and

Fig. 2 is a section on the line 2-2 of Fig. 1, with the crack-concealing strip positioned above the panels for assembling.

A house floor, wall or ceiling, herein termed a wall, may be formed of a set of panels II], I I, and I2 suitably nailed to joists or studs l3. The panels may be made of various materials but are ordinarily plywood. The crack l4 between the two panels Hi and I l is concealed by a wooden,

strip [5 cemented in a channel It so as to lie flush with the top surfaces of the panels m and ii. That channel 16, which may be formed by means of a plane, router, dado head or other sharp edged tool that is suitable for the purpose, may be made by grooving the border or edge portion of each panel so as to form a uniform channel width, even if the panel edges are not straight and the joint opening varies in con-.

tour.

The various panels may be made of plywood, such as the multiple-ply plywood illustrated in the drawings. A standard plywood comprises one or more central layers I8 (which would con-j sist of three inner layers in a 5-ply plywood) faced on the outside by veneer strips l9 and 20 that are cemented together by a quick setting resinous adhesive or other suitable material. The

grains of adjacent veneer layers are at right angles to each other, herein termed a criss-cross arrangement. The visible grain of the outer veneer layer is runs in a given direction as illustrated by the drawings and indicated by the arrows, and it is therefore desirable that the visible grain of the joint strip l5 run in the same direction so as to give an appearance of continuity of structure.

The strip is is preferably two-ply plywood made of two pieces of veneer cemented together by a quick setting resin cement. The top layer 2! is such that its grain lies parallel with the grain of the strips H1 and H. The under layer 22 has its grain arranged at right angles to the top grain. Thus, one veneer has its grain crosswise of the joint and so will give a desired strength to the cemented parts. Such a strip may be used either side up, so as to match the surface grain of the panels.

In the drawings which illustrate the parts in exaggerated size, the top layer 2| of the strip It may have substantially the thickness of the top veneer 19 or each panel. Hence, the shallo'w channel It is cut through that top veener is and into the center portion is of the panel deep enough to take the lower veneer portion 22 of the strip and a layer of cement 24 and leave the top of the strip flush with the panels.

The lower portion of Fig. 1 shows the strip l5 arranged to seal the joint between the two vertical panels l0 and H. The upper portion of the figure shows that a.further panel 25 may be mounted above the others, and the joint 2'! there between is partly concealed and strengtherred by a channel strip 28 lying in the channel 23 that is Suitably formed in the adjacent portions 'of the lower panels and the upper one. Since the exposed grain in all the panels is shown as running vertically, then the veneer strip 28, which is the same as the strip [5, is reversed so thatits crosswise grain shows as indicated in parallelism with the panelgraining. This arrangement insures that the grains of the panels and the strip 15 run in the same directions in each veneer layer of panel and strip so that the grains of the strips form substantially a continuation of the grains of the panel veneers.

The half channel or border groove in the joint edge of each of the panels H), H and 26 may be formed at the factory; but it is preferred to make each of 'theb'order grooves just prior to or after assembly of the parts on their support, since there are many places where the channel would not be required and this would compel the factory to furnish two kinds of plywood, one channeled and the other not. Also, if the panels did not fit flush together, the channel would therefore be too wide and a veneer strip of standard size would not fit, although it is desirable that the factory make up the two-ply joint strips as standard products. An electricallydriven rabbeting or routing tool arranged to cut a groove to a given depth and required width along the edge of the panel can be readily obtained for this purpose.

The strip I5 is preferably pre-fornied by initially cementing together two pieces of veneer by means of a Quick-setting resinous cement; but it is also feasible to assemble two separate veneer strips with an interposed thermosetting resin and to secure these strips together at the same time that they are cemented in the channel 16.

The cement employed to cement the strip in the channel as well as to secure the veneers to- 4 gether is a suitable thermosetting adhesive, such as a condensation product of a phenol and formaldehyde or other quick-setting synthetic resin which is hardened by heat toan infusible and insoluble condition.

Of the various cements which may be employed within the sco e or this invention, I prefer to use a phenol resin, such as the condensation product of phenol or resorcinol and formaldehyde, or a similar condensation productof urea or melamine with formaldehyde. Wide variations may be made in their compositions as. is well-known in the industry. These resins may be used in the form of a viscous solution of the monomeric or partially polymerized condensation product, or I may employ a thermosetting powder made of a suitable resin, such as a partially polymerized phenol resin, which is capable of melting and setting to an infusible condition. The resorcinol formaldehyde resin, sold as Penacolite, is available in both the liquid and powdered form. Urea formaldehyde is also available as a liquid or a powder. This will set either hot or cold. I may also use the resin in a sheet form, such as a thin paper impregnated with the resin in solid form. This is sold as Tego film. Such resins form joints that are stronger than the wood itself, and they are water proof and form barriers resistant to or proof against vermin, fungi; etc. The resins may be obtained as commercial products, or I may form them as needed. Resorcinol and formaldehyde may be mixed just prior to use and the resultant resin will set at a low temperature not much above F., so-that a structure may be assembled and made up into a strong and substantially integral structure both easily and quickly.

The thickness of the veneered strip 15 is of primary importance, since it is required that the strip be cemented in place in the channel It by a heat-hardened resinous cement. The heat is preferably applied by means of an electric heating iron, such as an ordinary household fiat iron or other device suitably made for the purpose. If desired, one may use a high frequency field suitably derived, provided there is adequate moisture in the cement; but I prefer to use a smooth surfaced metal tool that is heated by an electric resistance wire therein and which has a regulating switch and thermostat to control the heat. The thickness of the strip is such that the required heat may be transmitted through the wooden strip fast enough to set the resin without burning or scorching the wood. A temperature of 300 F. will serve to set a phenolic resin cement in a few seconds, and a higher temperature may be used depending on the total thickness of the veneer strip and the type of cement or glue that is used. A cement formed of the condensation product of resorcinol and formaldehyde is particularly suitable, since it will set at a temperature of about 110 F. or at a point where the transmitted heat will not injure the wood. If that cement is used, the veneered strip I5 may be safely made much thicker than herein specified.

I prefer to use standard veneers which are as thin as is consistent with the desired strength of the cemented joint. The veneers that are suitable vary from /20 to /as inch thickness, so that a 2-ply veneered strip will be about 0.1" or less in thickness. The preferred thickness of veneer is /48" or 0.0208 inch. This gives a total thickness of not over about 0.05" for the two veneer layers and the cement of a 2-ply veneered strip made of the /48" material. If a single veneer is used for the strip I5, I may employ the standard material that is /28 inchthick, or of other suitable thickness' This thickness of /48" veneer is preferred, since the 2-ply stock is not too fragile to .be cut and the veneer manufacturers have their machines set up to cut this thickness. However, veneers of different thickness may be employed, provided thecement will set under the heat conditions transmitted through the veneer within a reasonable period of time without scorching or otherwise injuring the wood. It is, of course, desirable to use a fast-setting cement so as not to delay the operator in setting up the structure.

The nature of the resin cement selected and particularly the rate at which it can be set by heat governs the type of veneer to be used, but the strengthbf the wood is also a factor. It is, however, essential that the veneer strip be so thin that it will conduct the heat readily for setting the cement. Hence, a bevelled or scarf joint or a V- joint between the ends of the panels would not be satisfactory for making a proper union, since the varying thickness of the woodprovided by the bevelled cuts would give a variable heat transmission. so that the thin edge of the wood would be overheated or scorched before the heat could be conducted through the thicker part of the bevelled end to set the resin. Hence, I prefer to have the strip l5 of a uniform thickness so that the heat transmission is the same throughout its extent. The veneer strip l5 may of course be as wide as desired for making a satisfactory and strong joint. I prefer that the strip be an inch or more in width so as to give a considerable area of bond between the strip l5 and the channel portions l6 of the two panels.

In installing the panels on the studs or joists of a building, the panels have the channels l6 and 29 initially cut in their edge portions, or the channels may be out after the panels are nailed in place. The panels are nailed onto the supporting frame and preferably as shown in Fig. 2 with the nails 30 driven through the channeled or reduced end portions of each panel, where their heads will be concealed by the channel strips l5. These nails are set into the panel so as not to interfere with assembling the strip. Thereafter, the layer of adhesive 24 is applied to the bottom of the channel or to the strip or otherwise interposed between the parts, and then a 2-ply veneered strip I5 or two separate pieces of veneer or a single strip of wood is firmly pressed into place. This strip has been previously manufactured so as to fit exactly into position. The carpenter holds the veneered strip in place with one hand, and with the other he runs an electric resistance flat iron, or other suitably heated tool over the strip, moving it slowly and progressively at the rate required to force the heat through the strip and cause it to set the cement Without injuring the wood. This rate may be varied widely depending on the resin used. For the resorcinol resin, an electric iron set for a moderate heat may be moved continuously along the entire strip in a fraction of a minute. That completes the operation, except that the exposed surfaces may be sanded or otherwise smoothed if needed, so as to be ready for paint or any other desired finish, or they may be left in a natural condition if desired.

This method of assembly may be employed to make various other types of structure. Although intended primarily for building walls and floors, it is applicable to the ceilings of buildings as well as in the production and assembly of counters, table tops or cabinets and other wooden articles where the joint between two panels or strips of wood or other material-is to be concealed and the parts are .to be secured together by a strip cemented in place, and particularly after the panels have been permanently secured on a supporting structure, such as a frame. a For some uses, a strip l5 may be cemented in place on both sides of two panels to be joined, thus making a much stronger joint, and in that case, the joining strip may be secured in place on one side of the panels, after which they may be mounted on the supporting frame, joists 0r studs with the cemented strip on the underside. Then the second strip is cemented in place on the exposed sides of the panels and so conceals the nails and the crack between the panels. Various other v modifications may be'made within the scope of this invention.

It will now be understood that the above dis closure is intended to set forth the principles of my invention and preferred embodiments thereof and not as imposing limitations on the appended claims.

. I claim: 7

1. A building wall structure comprising plywood panels of at least three-ply having layers of veneer in a criss-cross grain arrangement and assembled in an abutting relationship with a joint therebetween, the juxtaposed edge portions of two panels having grooves at each side of the joint providing a channel of uniform width having' the cross sectional dimensions of a two-ply plywood strip, a plywood strip of two veneers cemented together with their respective grains in a substantially perpendicular arrangement fitting within the channel and having the grain of one ply extending across the joint and the exposed surface of the strip flush with the adjacent panel surfaces, said strip being cemented to the bottom of the channel and forming with the panels an integral body having at least three plies cemented together at each side of the joint and two cemented plies over the joint.

2. A building wall according to claim 1, comprising supports and multi-ply plywood panels assembled thereon having their exposed grain markings extending in one direction and which are separated by both vertical and horizontal joints, the juxtaposed edges at each joint being grooved to form channels of two-ply depth, and similar two-ply veneer joining strips assembled in each of the channels, the strips in the horizontal and vertical channels being in a reverse grain arrangement and so arranged that the grains of the two veneers of each strip are substantially continuous with and extend in the same direction as the grains of the juxtaposed veneer layers of the adjacent panels.

3. The method of making a building wall structure of plywood comprising the steps of providing plywood panels having at least three plies of veneer in a criss-cross grain arrangement and a joining strip of two-ply plywood having two veneers of uniform width cemented together with their respective grains in a substantially perpendicular arrangement, assembling the panels in abutment and grooving their edges to form a channel of uniform width at the joint having the depth of two plies and the cross sectional dimensions of the strip, mounting the strip in the channel with cement therebeneath and with its face flush with the adjacent panels, the strip being so mounted that the grains of the juxtaposed veneers of panel and strip run substantially in the same direction and the grain of one veneer of the strip crosses the panel joint, and setting the cement c and thereby forming a plywood-sci at least three plies at each side of and two plies over the joint which is integral with the panel structure.

4. The method of claim 3 .in which two separate pieces of veneer are arranged in the channel with thermosetting cement between and beneath the same'and-wherein heat is progressively applied through both veneer strips to set the cement and secure the strips together aswellas to the panels. 1

5. The method of claim 3 in which the cement between the strip and-the bottom of the channel is a resin capableof thermosetting when heat is applied momentarily through the strip, and comprising the ste of progressively ap lying heat to the strip by movinga heated metal surface thereover at a rate and a controlled temperature which will thermally set the cement by heat transmission without scorching the wood.

6. The method of making a building wall panel structure of plywood comprising the steps of providing plywood panels having at least three integra-lly cemented plies of veneer in a criss-cross grain arrangement, grooving the panel edges to the depth of two plies to form achannel-of uniform width and the cross sectional dimensions, when the panels. are assembled, of a joining strip, providing said joining strip of not over 0.05 inch thickness which has two plies of veneer cemented together with their respective grains in a substantially perpendicular arrangement, fitting the REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,899,067 Trumbull Feb. 28, 1933 2,107,240 Eilertsen Feb. 1, 1938 2,253,667 Warner Aug. 26, 1941 2,291,116 Streater July 28, 1942 2,391,052 Hauptli Dec. 18, 1945 2,412,693 Pierson Dec. 17, 1946 2,440,936 Elmendorf et a1 May 4, 1948 OTHER REFERENCES Printed pubL: Detailed Super Harord Construction Applications, Published by Harbor Plywood Corpn, Hoquiam, Wash. January 23, 1945, D. 5.

30 (Copy in Div. 33.) 

